Sensitive photographic element



NOV. 3, 1936. D 2,059,829

SENSITIVE PHOTOGRAPHIC ELEMENT Filed Nov. 1, 1954 Elm.

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Patented Nov. 3, 1936 PATENT orrlcs snnsrrrvn rno'roomirmc E EMEN Erwin J. Ward, Rochester, N. Y., assignor, by W mesne assignments, to Eastman Kodak Comv pany, Jersey City, N. 1., a corporation of New Application 11 Claims.

This invention relatesto photographic elements including, particularly in the sensitive layer, a material which renders film and especially the emulsion less susceptible to abrasion, both before and after processing, as well as to decrease the coefficient of friction so that photographic materialmay be moved over a metal or other surface with less wear than would otherwise be the case.

I have discovered that if, to any ordinary gelatino silver halide emulsion or to gelatine, there is added a small proportion of 'wax or wax-like material, this desirable quality is much increased.

The method of preparation and the type of the emulsion is comparatively immaterial as my experiments have indicated that the wax is inert in ordinary emulsions and does not decrease their keeping properties. The types of emulsions and methods of incorporation may be those referred to in the patent Seel, No. 1,757,482, granted May 20 6, 1930.

In such emulsions or in any other gelatino silver halide emulsion I include a small proportion of wax". While I find carnauba wax particularly efiicacious, I contemplate the use of other natural waxes such as beeswax, Montan or Canto] wax, waxes of mineral origin, such as paraffin and synthetic waxes such as the chlorinated naphthalenes and chlorinated diphenyls, and I include all such substances under the term wax when used broadly in the claims. All of these compounds have softening or melting points higher than ordinary or room temperatures, 1. e., above about 20 C. and are therefore solid at ordinary temperatures.

35 An ordinary photographic emulsion can be easily scratched or dug with the finger nail, actually removing portions of the emulsion and leaving visible gouges, while with my improved emulsion, it is very diflicult, if not impossible to do more than slightly emboss the surface. In

ordinary usage therefore, there will not be produced scratches that may be filled with dirt. It is evidentthat this function of the wax is of importance primarily at or near the surface and the wax may be incorporated only in the outer stratum of emulsion or in an outer stratum of unsensitized gelatine applied to and unitary with the sensitized gelatine layer. These strata may be formed by successive coating operations as is common in photographic manufacture.

A satisfactory method for the introduction of the wax into the photographic emulsion or gelatine layer is to disperse the wax so that particles are of the order of magnitude of those found in silver halide emulsion, i.'e. from 1 to microns.

November 1, 1934, Serial No. 751,007

This may be accomplished through the use of various dispersing agents such as triethanolamine oleate. As an example, a carnauba wax dispersion in water with the dispersing agent is added to the gelatine. or to the gelatino silver halide emulsion by heating the latter to approximately 40 C. and introducing the wax dispersion with vigorous dispersion at this temperature. The dispersion may be made at any satisfactory concentration, but it has been found that 5% of carnauba wax is quite satisfactory, although I contemplate a wide. variation in proportions from .25. to 25 parts by weight of wax to 100 parts of dry gelatine.

Reference is made to the accompanying drawing, the two figures of which show on an exaggerated scale sections of film embodying different embodiments of my invention. In Figure l, l indicates any suitable support, preferably of a cellulose ester'composition, and 2 indicates the sensitive layer including wax as an ingredient.

In Figure 2, the support I carries a composite layer, the inner portion 20 of which is sensitive and free from wax and the outer stratum 2| of which is gelatine-wax layer of the type herein described and which may or may not be sensitized. A gelatine layer 22 containing wax may also be applied to the rear of the film. This layer may contain anti-halation dyes and would be formed in the manner described and have the properties mentioned of lessening friction. Other protein layers may be used, such as casein applied hot. This is then not removable in the processing bath.

While I contemplate the use of my invention particularly in motion picture and sound films, it is obvious that it may be useful in any photographic element, such as film packs, X-ray film and the like; and I consider as within my invention all such modifications and equivalents as may be covered by the appended claims.

Having thus described my invention, what I claim as new and desire to be secured by Letters Patent of the United States is:

1. A photographic element including a support and a gelatino silver halide emulsion thereon containing a small proportion of a wax which is solid at ordinary temperatures finely and uniformly dispersed therein.

2. A photographic element including a support and a gelatino silver halide emulsion thereon containing a small proportion of carnauba wax finely and uniformly dispersed therein.

3. A photographic element including a support and a gelatino silver halide emulsion there- 2 l on containing between V of 1% and 25% of a wax which is solid at ordinary temperatures finely and uniformly dispersed therein.

4. A photographic element including a support and a gelatino'silver halide emulsion thereon containing between 5/ of 1% and 25% of a natural wax of vegetable origin finely and uniformly dispersed therein.

5. A photographic element including a support and a gelatino silver halide emulsion thereon containing between V of 1% and 25% of carnauba wax finely and uniformly dispersed thereof, at least the inner stratum of said layer containing sensitive silver salts and at least the outer stratum thereof including a small proportion of a natural wax of vegetable origin finely and-uniformly dispersed therein.

8. A photographic sensitive element including a support,'on one face thereof a unitary gelatine layer containing a small proportion of wax finely and uniformly dispersed therein in the body of the layer, and on the opposite face thereof a sensitive emulsion layer.

9. A photographic element including a support and a unitary gelatine layer on one face thereof, the inner stratum of said layer, containing sensitive silver salts and the outer stratum thereof including a' small proportion of a wax which is solid at ordinary temperatures finely and uniformly dispersed in the layer.

10. A photographic motion picture film comprising a support of cellulose ester composition and a unitary gelatine layer on one face thereof, the inner stratum'of said layer containing sensitive silver salts and the outer stratum thereof including a small proportion of a wax which is solid at ordinary temperatures finely and uniformly dispersed in the layer.-

-l1. A photographic motion picture film com; prising a support of cellulose ester composition and a unitary gelatine layer on one face thereof, the inner stratum of said layer containing sensitive silver salts and the outer stratum thereof including a small proportion of a natural wax of vegetable origin finely and uniformly dispersed therein.

' ERWIN J. WARD. 

